The Relationship Between Autoimmunity and Chagas’ Disease: Causal or Coincidental?

Abstract

Trypanosoma cruzi infection or South American trypanosomiasis is a major public health problem in Latin America, where it affects in the order of 10–12 million individuals. The distribution of the parasite in animal reservoir hosts extends far beyond that of human infection to include, for example, the Amazonian basin of Brazil and even the southernmost states of the United States. Although fully infectious to a human host, the parasite is not usually transmitted from wild animal reservoir hosts to the human population in these areas because of the lack of suitable vectors. However, recent studies have shown an incursion of sylvatic cycles of transmission into the peridomicilary habitat because of changes in farming practice or socioeconomic conditions. Similarly, the geo-graphical range of human infection and vector distribution has also changed because of population migration. In this way, T. cruzi infection is not diminishing but shows every indication of a future increase. One contributory factor to this likely increase is the growing number of cases of infection via blood transfusion (Brener 1979). For economic reasons, blood donations in Latin America tend to ascend the social scale, from donor to recipient, and as a consequence so does blood-borne infection. This change in the pattern of infection has produced a growing awareness of T. cruzi and Chagas’ disease among relatively well-developed urban populations, and thus even greater pressure for its control and elimination by chemotherapy, vaccination or public health measures.